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Historic, archived document 

Do not assume content reflects current 
scientific knowledge, policies, or practices. 

CIRCULAR No. 386 APRIL 1936 



By WARREN WHITCOMB, Jr., associate apiculturist, Division of Bee Culture, 
Bureau of Entomology and Plant Quarantine 

; Page Page 
Economic importance and sources of loss-___-__- 1 | Other moths causing damage to stored combs... 8 
Estonyaandedistribution iss ess nea aie Sul Natural controlics. ses ae see ce a aene ee a= 8 
Tifemhistony see oe eee eee AR WAT titi clalkcomtroleeee: Staessen 9 
MN GYS) Ce Ae se oe OE ee 4 |. Control measures under apiary conditions. 9 
SON a Vas ee te ee Se a A a 4 Control measures in stored equipment____. 9 
PANY OVE) 4 ODT OYE ees oe eat I Sse em ect ee 6 Control measures in stored comb honey... 1 
DOVE WEKo kU Ree es Sa ee ae ea 7 

The wax moth (Galleria mellonella L.) is known under many 
names in different sections of the United States. Beekeepers know 
the insect as the “ wax moth”, “bee moth”, “bee miller”, “ wax 
worm ”, “ web worm ”, and “ wax miller.” It is better known in the 
larval or worm stage than as the adult or moth and is therefore 
generally referred to as the “wax worm” or “ web worm.” 


No careful estimate has ever been made of the damage: caused by 
the wax moth. The losses in Texas were at one time estimated at 
5 percent, and in 1911 reports from 186 Texas beekeepers placed 
colony losses at from 5 to 95 percent, according to Texas Agricul- 
tural Experiment Station Bulletin 231. Losses in the Southern 
States are considerably higher than in the North because of the 
longer season of bee and moth activity. Moreover, apiary practices 
in the South, especially that of keeping empty combs on the colonies 
during long, slow honey flows, increase the opportunity for wax moth 
damage. The complete destruction of colonies, however, does not 
represent the total of wax moth damage, since combs in supers may 
be ruined even when the colony is of fair strength. This 1s partic- 
ularly true when two or more hive bodies are placed on the colonies 
during slow flows, or late in the fall for storage. 

Probably the most noticeable loss from wax moth injury is in 
combs in storage, especially if these combs are in a warm, pro- 
tected place, and consists in the destruction of the combs by the 
larvae, which leave them a mass of webs and debris (fig. 1). In 
the North such losses are more common than the destruction of 
entire colonies. 

36749°— 36——1 


The larvae of the wax moth cause a considerable amount of dam- 
age each year to comb honey. The eggs of the wax moth are prob- 
ably laid on the comb or section boxes before the comb-honey supers 
are removed from the hives, but the damage usually occurs some 
time after the honey has been placed in storage. The damage con- 
sists of small, rather inconspicuous tunnels and borings through the 
thin wax cap of the honey cells. These small holes through the 
cappings cause the honey to leak out, which makes the affected sec- 
tion unmarketable. This type of damage is sometimes termed 
‘“ weeping.” ) 

A rather indirect loss that might be charged to the wax moth is 
the winter loss of colonies in the Southern States. Owing to the 
necessity of preventing wax moth damage to stored combs after 

FIGURE 1.—Webs and tunnels made by larvae of the wax moth in a comb. 

extracting, and the expense of storage room and treatment for such 
combs, many beekeepers store supers of these empty combs on the 
colonies during the winter. This gives added room for the bees to 
occupy during a warm spell, and a sudden change in temperature 
may chill or even kill. them before they can return to the cluster. It 
also gives an opportunity for the dissipation of colony heat and 
thereby increases the quantity of food consumed by the bees, and, 
during long periods of cold or inclement weather, weak colonies or 
colonies short of stores may starve. In many such cases of starva- 
tion the wax moth destroys the combs before the beekeeper becomes 
aware of the death of the colony. 


In any study of the economic importance of an insect, not only 
the loss but the benefit from the insect must be weighed. The wax 
moth is not an unmitigated evil. In the first place, the destruction 
of combs by the wax moth has not only tended to prevent the keep- 
ing of bees in box hives but has also tended to improve general bee- 
keeping practices. The wax moth has also been an ally of the bee- 
keeper by helping to destroy combs in bee trees or other inaccessible 
places, which might harbor germs of some of the brood diseases. 

Since bees in box hives cannot be examined, requeened, or other- 
wise controlled, the colonies are likely to become weak, and under 
such conditions an invasion of the wax moth destroys the colony 
and the combs. Many States have laws to prevent the keeping of 
bees in box hives, and the wax moth has furthered the aim of this 
legislation by destroying such colonies in its spread. So thorough 
is the destruction of colony and combs in most box hives that, unless 
there are large stores of honey in the hives, bees are no longer 
attracted to them. 

Particularly in the Southern States, where the honey flow is slow 
and extends over a long period, it has become a practice to give more 
super room at the beginning of the flow than the bees actually need. 
This is not the best practice if a large crop of honey is desired, and 
the destruction of such unprotected combs by the wax moth has been 
of direct benefit to beekeepers in forcing a change of method. 

The destruction by wax moth larvae of combs in bee trees is prob- 
ably a great aid in preventing the spread of bee disease through the 
robbing of honey by other bees and, in those areas where queen 
breeders and package shippers are located, the destruction of stray 
colonies has also been of real value. Since the germs of American 
foulbrood have been found in the excrement of wax moth larvae 
there is a theoretical possibility that the disease might be spread 
by this means, but actually there is no evidence to warrant pinning 
additional guilt on this pest. 

The benefits of the wax moth are small, however, when compared 
with the losses of entire colonies and of stored combs, or the extra 
care and manipulation necessary to combat the insect. 


The earliest works on beekeeping contain references to the wax 
moth. Aristotle (884-822 B. C.), Virgil (70-19 B. C.), and Colu- 
mella (middle of the first century, A. D.), all mention the wax moth 
as an enemy of the honeybee. | 

The range of foods that can be eaten by the larvae of the wax 
moth would suggest that it might at one time have had other foods 
than those obtainable in the hive, but at present wax comb in some 
form is practically its only food. 

F. B. Paddock, who has made a study of the present-day distribu- 
tion of the wax moth, was unable to determine the date of its intro- 
duction into the United States. From his distribution records some 
interesting inferences may be drawn: (1) The wax moth has been 
spread by man more than by the natural activity of the moth. The 
introduction of the moth into Sweden with beehives from Germany 
prior to 1750 and its introduction into Australia, New Zealand, and 
other island regions all point to the conclusion that the wax moth 


must have been aided in its distribution by man and by poor bee- 
keeping methods. (2) The insect finds its most favorable conditions 
in the Temperate Zone. According to Paddock, the wax moth is 
present in Ontario, Canada, but has been unable to establish itself 
in Manitoba and British Columbia. The high altitudes of the Rocky 
Mountains are also free, but the wax moth can be found almost any- 
where else in the United States where there are bees. 

In the Southern States the wax moth does damage practically 
throughout the year, with the possible exception of December, Jan- 
uary, and February; and during mild winters wax moths may ap- 
pear even in January. It is probable that colonies are infested, at 
least with eggs, throughout the whole season of bee activity and that 
only in active colonies is wholesale damage prevented. In supers 
and hive bodies brought from the apiary and stored, larvae of all 
stages will be found, ordinarily within a week, unless the combs are 
treated. Under storage conditions, the lengths of the egg, larval, and 
pupal stages vary considerably, and the number of broods per year 
is largely determined by temperature and humidity. Distribution, 
under such conditions, is rapid because of the movement of combs 
and bee equipment, even without the active flight and dispersion of 
the adult moths. 



The egg of the wax moth is small, white, somewhat elliptical, and 
rather inconspicuous (fig. 2). It measures about one fifty-fourth of 
an inch in greatest length and about one-sixtieth of an inch in great- 
est width. The size and shape vary somewhat, depending on the 
number of eggs laid in one spot and the character of the site in which 
they are laid. 

At 75° to 80° F. the eggs hatch in from 5 to 8 days, but with low 
temperatures (50° to 60°) the period may extend to 35 days. Under 
aplary conditions the incubation period is probably almost entirely 
dependent on temperature. 

The eggs of the wax moth are probably laid most frequently in 
the cracks between hive parts; that is, between supers, between hive 
body and bottom board, or between the super and cover. Egg masses 
have been found in cracks between the inner cover and top super of 
the hive, where they had been deposited by the female, apparently 
from the outside of the hive. Eggs are also laid inside the hive in 
more or less unprotected places. Under controlled conditions, when 
females were allowed access to combs, the eggs were found on the 
comb (fig. 2) along the edges of the frames and almost always in 
the portions of the hive farthest from the light. Egg masses in the 
hive are difficult to see and may often be overlooked. 


The young larvae, upon hatching, are very active and do not look 
like the familiar wax worms. Beekeepers have called them wood lice 
and have not connected the appearance of these forms with the dam- 
age from the worms, which they noticed later. They are often seen 
upon the inner covers of hives and in the cracks between supers and 


hive parts. They are less often observed within the hive, especially 
those with strong colonies, partly because they are very small and 
very active, and partly because they resemble the wax in color. 

The young larvae attempt to burrow into the wax almost imme- 
diately after emergence from the egg. The first burrows are often 
incomplete and may be mere roughenings of the surface of the wax. 
After the first day, however, they make small tunnels between the 
cells and toward the midrib of the comb, in which the typical silken 
strands of the web may be found. 

The growth of the larvae depends upon several factors, of which 
the quantity and quality of food and the temperature are most 

FIGURE 2.—Eeggs of the wax moth laid on a comb. Greatly enlarged. 

important. The length of the larval period, from the time of the 
hatching of the egg until pupation, has been found to range from 
28 days to 4 months or even as long as 140 days or nearly 5 months. 
During this period the large larvae have grown from about one 
twenty-fifth of an inch to seven-eighths of an inch in length. 

The food of the larvae is not confined to beeswax, and it is even 
probable that little pure wax is digested but rather that the larvae 
derive most of their nourishment from the impurities in the wax. 
Foundation, especially in frames, is seldom attacked and then usually 
only by the small larvae. In some cases newly emerged larvae have 
been seen chewing, or attempting to chew, other larvae which had 
been injured. . 

The larvae prefer the darker brood combs to the white extracting 
combs. In the brood combs the larvae confine their work mostly 
to the midrib and bases of the cells, and combs are often found with 
perhaps the outer one-fourth of the length of the cells untouched 
and the central portion, including the midrib, completely destroyed 
and replaced with a mass of web and refuse. Under such conditions 


the cells containing pollen are mostly avoided, although cells con- 
taining honey may be riddled. It is known, however, that larvae 
will eat pollen and develop on it. Wax moth larvae sometimes chew 
off the cappings of the cells containing sealed brood, and, while the 
bees may repair some of the damage, many cells will be left only 
partially closed. 

Although larvae can develop on foundation, the mortality of such 
larvae is high, and the developmental period of those which survive 
is much longer than that of normally fed larvae, and the resulting 
adults are small and almost white. It is almost certain that damage 
reported by beekeepers in Louisiana as caused by the lesser wax 
moth (Achroia grisella Fab.) is caused by such poorly fed larvae of 
Galleria mellonella, since no specimens of the true lesser wax moth - 
were observed during the author’s studies. When the larvae are 
forced to exist on the lighter comb and the outer portions of the 
cells which have been left untouched by the previous broods, the 
damage done by them, such as the webbing and external feeding, 
and their later appearance greatly resemble the work and appearance 
of the lesser wax moth. 

The optimum temperature for the development of the larvae is 
between 85° and 95° F., about that normally found in a beehive 
during the active season. At lower temperatures development is 
slower, but, unless the temperature falls below 60°. no other influence 
on the larva has been noted. At temperatures of 40° to 45° the 
larvae seem to become dormant, and no feeding or growth takes 


Before pupation the full-grown larvae spin a dense, tough, silken 
cocoon. Usually this cocoon is firmly attached to the side of the 
hive, to the frame, or other solid support, but in some cases the 
cocoons are found in the mass of tunnels and refuse of the wax of 
the frames or on the bottom of the hive (fig. 3). In many cases a 
hollow is chewed out of the wood of the hive or frame, and the 
cocoon is placed in this for added protection. Frames may be found 
in which holes have been bored completely through the end or top 
bars, and the cocoon and pupal case will be found inside these 
holes. This habit of the wax worm is responsible for a considerable 
part of the damage caused by the insect, since in heavily infested 
colonies not only the wax but also the frames are destroyed. In such 
cases particles of the wood borings are incorporated in the cocoon, 
which is then well disguised. The fully grown larvae migrate to 
considerable distances before the cocoons are spun, and pupal cases 
may be found beneath the hive and even on the more protected 
parts of the hive stand. 


Within the cocoon the larva changes to the pupa. The duration 
of the pupal stage within the cocoon ranges from 8 to 62 days, 
depending on temperature. As with many other insects, the pupal 
period allows the wax worm to pass through the fall and winter 
protected against climatic influence to a large extent. In the South, 
especially during warm winters, the adults may emerge at any time 
during the winter. 


The adult wax moths are about three-fourths of an inch in length 
and have a wing spread of about 1 to 114 inches in well-developed 
specimens. They are commonly seen in the resting position with 
thaw grayish-brown wings folded, rooflike, closely about them 
(fig. 4, A and B). The moths are not easily disturbed, but when 
molested they run rapidly before they take wing. The males are 
slightly smaller than the females and may be distinguished from 
them by the shape of the outer margin of the fore wing, which is 
smooth in the female but roundly notched in the male. The sexes 

FIGURE 3.—Pupal cases, or cocoons, of the wax moth. 

may also be distinguished easily by the palpi of the mouth parts, 
which are prominent in the female but absent in the male. 

The moths vary widely in size and color, according to the type of 
food consumed by the larvae and to the length of time of develop- 
ment. Small, poorly nourished larvae, or those which, because of 
low temperatures or other factors, develop slowly, transform into 
small adults, sometimes less than half the normal size. Such small 
adults might easily be confused with the lesser wax moth. Larvae 
fed on dark brood combs transform into adults which may be dark 
gray to almost black, while larvae which survive on pure wax, or on 
foundation, transform into moths that are silvery white and smaller 
than those reared on brood comb. 

The female starts depositing eggs from 4 to 10 days after emergence 
and continues depositing them as long as her bodily vitality lasts. 
Egg laying may be rapid at times, and as many as 102 eggs have been 
deposited by a female in 1 minute. The total number of eggs laid by 


a female varies to a considerable extent under laboratory conditions, 
but it is usually less than 3800. The adults may live as long as 3 weeks. 


It seems doubtful whether there are definite generations of the wax 
moth during different periods of the year in the Southern States. 
Rather it is probable that the moth is always present, that larvae in 
all stages, pupae, and adults may be found at any time, and that devel- 
opment goes on except during periods of low temperature. 


Ficurre 4.—Adults of the wax moth: A and B, With wings folded; C and D, with wings 
spread; A and C, females; B and D, males. Note the deep clefts in the tips of the fore 
wings of the male, 


Mention has been made of the lesser wax moth, but this moth does 
not cause so much damage to stored combs as does the wax moth. ‘The 
work of the lesser wax moth is similar to that of the wax moth, but 
the tunnels are smaller, the webs finer, and feeding and webbing are 
more confined to the outer surface of the combs. The Mediterranean 
flour moth (L'phestia kuehniella Zell.) is a pollen feeder rather than 
a wax feeder but does some damage to combs by boring tunnels 
through the midrib. This moth also tunnels into brood cells and 
consumes the food intended for the developing bee larvae. These 
moths, also, may be controlled by the methods given in this circular. 


The bees are the greatest and most effective natural enemies of the 
wax moths. They will, when the colony is strong, carry them bodily 
out of the hive, and there is no better insurance against the ravages 
of the pest than to have the combs populated with a strong colony 
headed by a vigorous queen. 

A small red ant (A/onomoriwm sp.), which seems to have a wide 
range of foods, has been quite effective in controlling the wax moth 
in laboratory experiments by feeding on resting wax moths during 
daylight, but it has not been observed attacking larvae in combs under 


apiary conditions. The ant seems more attracted to honey and pollen 
than to the wax moth in stored combs. 

Comparatively little is known of the other insect enemies of the 
wax moth, and not much benefit can be expected from them. 

Climatic conditions, particularly temperature, are effective in limit- 
ing the spread of the wax moth, and the rate of growth, and thereby 
the amount of damage done by the insect. 



Two phases of artificial control for the wax moth must be dis- 
cussed, (1) the control measures for colonies under apiary conditions, 
and (2) control of the wax moth, or prevention of its damage, in 
stored equipment. 

Under apiary conditions, the best control is in keeping colonies 
strong. Added to this should be cleanliness of hives—removal of 
propolis, bur combs, and refuse on the bottom board which provide 
protection for larvae of the wax moth. Even in strong colonies, 
developing larvae of the wax moth may often be found beneath the 
comb burs on the bottom board or in propolis and bur combs in the 
less accessible portions of the hives. Accidental loss of queens in 
such colonies late in the fall may mean the loss of colonies from wax 
moth damage before the first spring examination. . Beekeeping prac- 
tices and manipulations should be based on the assumption that. the 
wax moth in some stage may be present in the hives at all times. 

The box hive, or a hive in which the frames are not easily movable, 
gives the wax moth an opportunity to reproduce, and forms a breed- 
ing place from which other colonies may be attacked. From the 
standpoint of both productive beekeeping and wax moth control, such 
hives should be destroyed and replaced by modern equipment. 

Control of the wax moth by trapping the adults at hghts or by 
trap combs has not been successful. The adults are not attracted to 
lights and trap combs evidently are not more attractive. 


For controlling the wax moth on equipment in storage, two methods 
of attack are possible. Some substance may be used which will kill 
the wax moth or some method adopted of repelling the adults so that 
eggs are not deposited on the stored equipment. Of the killing sub- 
stances, fumigants (poisonous gases) have proved most satisfactory, 
but, with the exception of paradichlorobenzene, the gases do not 
remain in the supers long enough to have any distinct repellent action. 

Fumigants for wax moth control are substances, whether liquid or 
solid, that form a killing gas that diffuses through the stored equip- 
ment and is taken in by the insect. Several different substances have 
been used with success against the wax moth, particularly paradi- 
chlorobenzene and carbon disulphide. 


Paradichlorobenzene (“PDB”) is a white crystalline substance 
which changes slowly into a gas. The gas is not unpleasant to smell, 
is noninjurious to people at the concentration obtained when used as 


directed, and is heavier than air. It is noninflammable and nonex- 
plosive. It kills adults and larvae of the wax moth but is not 
effective against the eggs. 

In fumigating with paradichlorobenzene, the supers should be 
stacked as tightly as possible and the cracks between supers covered 
with gummed paper strips (fig. 5). A generous handful of the crys- 
tals should be placed on the top of the frames of the top super and 
the cover put tightly in place. The crystals may be sprinkled di- 
rectly on the top bars of the frames, as in figure 5, or put on a piece 

FIGURE 5.—Supers loaded with comb ready for fumigation. The joints are sealed with 
gummed paper tape, and the crystals of paradichlorobenzene have been sprinkled 
heavily over the top bars. 

of paper laid on the top bars. Since the gas is nonpoisonous and 
not disagreeable, treatment may be made in ordinary storage without 
taking the infected material out of doors. At intervals during the 
storage season the covers of the stacks should be raised, and unless 
some are still present, more crystals added. 

Paradichlorobenzene is at present as cheap as any of the materials 
mentioned in this circular, with the exception of sulphur, and is by 
far the easiest and least dangerous to use. The crystals last for some 
time, since they volatilize slowly, and not only kill the larvae and 
adults first present and the larvae as they hatch from the eggs, but 
repel moths from outside which might otherwise enter and start a 
fresh infestation. Paradichlorobenzene is most effective at tempera- 
tures above 70° F. and volatilizes more rapidly as the temperature 
rises. Inspections of stored materials should be made at intervals 
of 2 or 3 weeks, depending on the temperature of the storehouse and 
the prevalence of adult moths, 



Carbon disulphide has been a standard fumigant for wax moths 
and similar insects until recently, and with proper precautions is still 
satisfactory. As commonly sold commercially, it is a more or less 
yellowish, somewhat oily liquid that changes readily at ordinary 
temperatures into an ill-smelling gas. The hquid is about one-fourth 
heavier than water, and the gas is heavier than air. Jt is highly 
inflammable, and the vapor is explosive when mixed with ar in 
certain proportions, and therefore this chemical must not be handled 
around fire of any kind. Preferably it should be used out of doors 
or in a well ventilated or open shed. 

In using carbon disulphide the supers should be sealed in the 
same manner as for paradichlorobenzene. One ounce of liquid is 
sufficient for five supers, and more than this number of supers should 
not be placed in a single stack, since the weight of the gas carries 
it quickly to the bottom of the stack, and the top super may not be 
adequately fumigated. The stack should remain sealed for not less 
than 12 hours. Carbon disulphide is effective against larvae and 
adults but not against eggs; consequently, it may be necessary to 
repeat the treatment after any eggs have had time to hatch. 


Other substances may be used for the control of the wax moth in 
stored equipment, but, as explained in the following paragraphs, 
they are not so efficient for this purpose as either paradichloro- 
benzene or carbon disulphide and are therefore not recommended. 

The fumes from burning sulphur effectively control the larvae and 
adults of the wax moth but are ineffective against the eggs. Sulphur 
was one of the earliest of the substances used to control the wax 
moth in stored combs. The early method was to stack the supers 
over a pan of live coals over which was sprinkled powdered sulphur. 
About 2 ounces of powdered sulphur (flowers of sulphur) is suffi- 
cient for a stack of five supers. At least one empty super should 
be placed at the bottom of the stack so that the heat will not melt 
the combs. Present-day practice is to put the sulphur in a dish, 
wet it with denatured or wood alcohol, and ignite it directly. The 
work should be done in a well-ventilated room or out of doors, and 
precautions must be taken against ignition or overheating of the 

Calcium cyanide is effective against the larvae, pupae, and adults of 
the wax moth, but cannot be depended on to destroy the eggs. It 
is obtainable either as dust or as fine or coarse crystals. For use 
in fumigating bee equipment the crystals are preferable to the dust. 
In the presence of moisture (such as that found in the air) the 
crystals form a deadly gas, noninflammable and nonexplosive, but 
extremely poisonous to people and animals. Care must be taken 
when using the substance, and the gas must not be breathed. For 
use put one full tablespoonful of crystals on a sheet of paper and 
place the paper on the top of the frames in a super. Quickly place 
the other supers on top, using not more than five supers per stack, 
and tape the joints between supers with gummed paper tape. The 
fumigation should be done out of doors, or in a well-ventilated room. 


Leave the stack for at least 12 hours before disturbing it, and air 
the supers well before storing them. 

Carbon tetrachloride is effective against wax moths, but does not 
have enough penetrating power to kill larvae in cocoons or in thickly 
webbed refuse. It is a colorless liquid with a sweetish, disagreeable 
odor. The gas formed is heavier than that of carbon disulphide, 
and it is used in the same way. ‘The gas is noninflammable and non- 
explosive, but poisonous. : 


Use not more than five supers in a stack and seal the joints with 
gummed-paper tape to make the stack gas tight. With gases heavier 
than air, make sure that the base of the stack is tightly closed, since 
the gases sink to the bottom of the stack and may escape. A pad of 
newspapers placed beneath the stack will help to confine the gas. 

Fumigate out of doors, if possible, or at least in a well-ventilated 
room. Read carefully the directions for using the selected fumigant 
and have everything in readiness before fumigation is begun, espe- 
cially if cyanide is to be used. 

Caution.—Carbon disulphide gas is highly explosive, and any 
chance of ignition must be carefully guarded against. Both carbon 
disulphide and. calcium cyanide and their gases are poisonous to 
people and to animals and must be stored and handled with extreme 

When using paradichlorobenzene, put the crystals directly on the 
top bars of frames of the top super, as shown in figure 5, or on a 
paper laid on the top bars, and renew them throughout the season 
whenever the crystals have disappeared. . 

As the other fumigants mentioned are not effective against rein- 
festation from hatching eggs, examinations must be made at intervals 
to see if any eggs have hatched, especially if the storage room is 
warm. If the temperature is above 70° F., repeat the treatment after 
2 or 3 weeks. The stacks being fumigated must be kept sealed for at 
least 12 hours, and preferably for 24 hours. 

Air the combs thoroughly before placing them on the hives. 

Table 1 gives an outline for reference in fumigating against the 
wax moth. 


The control for wax moth damage to stored comb honey is the same 
as for other stored comb products. The supers should be removed 
from the colonies as soon as possible after the flow ceases and piled 
in tiers of not more than 8 to 10. All joints between supers should 
be covered with paper, and the bottom of the stack should be sealed 
to prevent leakage of gas. Paradichlorobenzene crystals should be 
sprinkled over the sections of each super as it is placed in the tier, as 
well as on the sections of the top super, since circulation of air is 
poor in such stacks. The treatment should be continued until the 
honey is graded and marketed. Carbon disulphide may be used 
according to the directions given, if desired. 





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Secretary of Agriculture_______ = d Henry A, WALLACE. 

Under Secretary 22 ae ee ReExrForD G. TUGWELL. 
Assistant Secretary______-—__ =i Bie _ M. L. WIxson. 

Director of Extension Work_.~------------_ C. W. WARBURTON. 

Director. of. Personnels ee W. W. STOCKBERGER. 

Director of Information_-__ __-—==eee ss M. S. EISENHOWER. 

DireCtor Of el inane a2 ea es See eee eee W. A. JUMP. 

NSOUGIIOT 2 2e= ee ke a See eee MASTIN G. WHITE. 
Agricultural Adjustment Administration_____ CHESTER C. Davis, Administrator. 
Bureau of Agricultural Heonomics___________ A. G. BLAck, Chief. 

Bureau of Agricultural Engineering_________- S. H. McCrory, Chief. 

Bureau of Animal Industry_________________ JOHN R. MoHLER, Chief. 
Bureau of Biological Survey_— oF a meas — IRA N. GABRIELSON, Chief. 
Bureau of Chemistry and Soils__-__________ H. G. Knigut, Chief. 

Bureau of Diiry Industy = ee O. E. ReEeEp, Chief. 

Bureau of Entomology and Plant Quarantine. Lem A. Strone, Chief. 

Office of Hxperiment Stations_______________ JAMES T. JARDINE, Chief. 

Food and Drug Administration— _.....__ WALTER G. CAMPBELL, Chief. 
Ronestaservice = zs __. FERDINAND A. Siuncox, Chief. 
Grain Futures Administration_________--__-_ J. W. I. DUvEL,;. Chief. 
Bureau of Home Heonomics__ — === Louise STANLEY, Chief. 
LAOTONY) 2 S252 ee 2 he 5 ee eee CLARIBEL R. BARNETT, Librarian. 
Bureau of Plant Industry____________-___-__ FReperick D. Ricury, Chief. 
Bureau of Lubic kos Se THomas H. MacDona.p, Chief. 
Sou, Conservation Service H. H. BENNETT, Chief. 
Weather Buredu___--_-_-—-— ake oes WHELs Re GRecG sO iver. 

This circular is a contribution from 

Bureau of Entomology and Plant Quarantine__. Ler A. Strone, Chief. 
Division of Bee Culture eee JAS. I. HAMBLETON, Principal Api- 
culturist, in Charge. 


For sale by the Superintendent of Documents, Washington, D, C. - - - - - - Price 5 cents 

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